To understand why Cruz stands a chance against Trump, it helps to look at his Wisconsin win. The state’s GOP is representative of the “establishment” but not in the usual, out-of-touch sense. It is an establishment party because it is profoundly partisan. Earlier in the 2016 campaign, local pundits and early polling gave Marco Rubio a good chance in Wisconsin before he suspended his campaign; John Kasich would seem to have been a good stand-in for sunny, common-sense Republicanism. But Cruz’ conservative, sometimes religious appeals were not a natural fit for Wisconsin, despite its Baptist governor. And Trump’s appeal to lower-income, blue-collar, and less-observant Christians had some traction in the northern and western reaches of the state, yet exit polls yesterday suggested that Cruz broke through even with the less religious.

See also: Cruz’s Wisconsin Win Could Put Nomination Out of Trump’s Reach

But, unlike other states’ contests, identity and ideological politics were not what drove the GOP primary. Instead, voters from the governor to conservative talk show hosts to party regulars, viewed Trump as a mortal threat to the Republican Party. Since such polling began in the U.S., neither party had nominated a candidate with higher negatives than Trump across a greater spectrum of the American electorate, nay, even from its own partisans. In Wisconsin, 58% of GOP voters said they were either “concerned” about or “scared” of a Trump presidency. The Wisconsin primary showed the awakening of an older, more storied, kind of American political party. Republicans may chafe at the prospect of an unruly nominating convention in July, but the fractures in the party lie deeper in its structure. They have roots in the even more raucous presidential election of 1824. That year featured four candidates, all from the same Democratic-Republican political party. None of the candidates prevailed at the polls. They might have dreamt of a contested convention, but instead they got something worse — the election was thrown to the House of Representatives. There, after backstabbing and machinations that Andrew Jackson’s supporters called a “corrupt bargain,” the House chose John Quincy Adams.

Martin Van Buren, the 8^th president of the U.S. and a Jackson supporter, hated Adams and vowed to replace him with the Tennessean at the first possible opportunity. His challenge was to supplant Americans’ local pride with partisan fervor, or, as he told a Virginia newspaper editor, to substitute “party principle for personal preference.” Van Buren’s new machine, the mass-based Jacksonian Democrats or Democratic Party, was the embodiment of the principle, and he successfully forged the world’s first such organization. In it, individual politicians were to accommodate the views of their constituents, but the party would have no positions, ideology, or principles. Meaning they would take any position or abandon an earlier one in pursuit of victory.

But cracks in this system began to appear in the late 1960s as candidates felt boxed in by party elders’ milquetoast approach to politics. These candidates would campaign for themselves. And they campaigned on issues to the angst of some and the anger of others. Voters responded by splitting their tickets between parties, a phenomenon that spiked in 1972 when nearly 30% of voters selected candidates from both parties in November. The parties answered by opening the nomination process, therefore reducing the power of party leaders and bosses to control delegations to the national conventions. In a fundamental inversion of Van Buren, party elites thought that giving their loosely-attached voters a say on the direction of the party, voters would return to the partisan fold. The parties would stand for principles even if principles endangered partisan and national unity. In Wisconsin, Cruz showed that he could win formerly skeptical voters so long as they adopted Van Buren’s “partisan principle.” Indeed, he drew almost as much support from Republicans who favored a path to citizenship for illegal immigrants as from those who favored deporting them.

In a significant boost to Cruz, Wisconsin Republicans thought Cruz could “bring needed change,” one of Trump’s typical strengths. Cruz may not be their dream candidate — only 35% of GOP voters said the main reason to support Cruz was shared values — but at least he polls close to Hillary Clinton in general election match-ups. For Cruz to hold on, though, he will have to take Van Buren’s — and Vince Lombardi’s — other advice to Jackson: Winning isn’t everything, it’s the only thing.

Arnold F. Shober is an associate professor of government at Lawrence University in Wisconsin.